The field of the present invention is mechanisms for delivering power from an engine to propel a vehicle.
A wide variety of drive train configurations have been employed since the inception of motorized vehicles. Multiaxled drives have been used as well. Of late, drive trains capable of driving through all four wheels have attracted greater interest. This interest extends from off-road vehicles to race cars.
A conventional drive train for four-wheel drive vehicles includes an engine longitudinally mounted in the vehicle with a clutch/transmission assembly extending rearwardly from the engine. A short drive shaft is coupled between this assembly and a transfer case. The transfer case is typically mounted to the underside of the vehicle where it impacts on overall ground clearance. Such devices typically include a high/low transmission and a gear train for distributing power to the rear wheels on a constant basis and power to the front wheels on a selected basis. Differentials are then positioned front and rear to receive the power and distribute it to the wheels. Such systems lack versatility because of component length, required location of the transfer case, and the number of required components.
Advances in drive train components have made possible more usable four-wheel drive systems. The changing of operating modes on the fly in providing four-wheel drive automatically on demand are now becoming more universally available.
The drive components such as the high/low transmission gearing tend to be subjected to high torque loads because of location in the drive train. A lack of versatility of component height and ground clearance also exists because of necessary engine placement, component intrusion into the interior space of the vehicle, and efficient drive line considerations.